


Upheaval

by StellarRK



Category: Haikyuu!!
Genre: Aged-Up Character(s), Alpha Tsukishima Kei, Alpha/Beta/Omega Dynamics, Alpha/Omega, Future Fic, Hinata Shouyou & Tsukishima Kei Friendship, M/M, Mating Cycles/In Heat, Omega Hinata Shouyou, Omega Yamaguchi Tadashi, Omegaverse
Language: English
Status: In-Progress
Published: 2019-11-19
Updated: 2020-04-13
Packaged: 2021-04-03 17:09:57
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 4,240
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21485155
Author URL: https://archiveofourown.org/users/StellarRK/pseuds/StellarRK
Summary: Yamaguchi presents late and things get complicated
Relationships: Tsukishima Kei/Yamaguchi Tadashi
Comments: 8
Kudos: 271





	1. the incident

Yamaguchi was still unpresented which wasn’t quite normal for a high schooler, especially a 3rd year, but of course it wasn’t unheard of for someone to go unpresented their whole life for whatever reason. Though Yamaguchi didn’t seem to notice or care much and neither did most people, he was tall and a bit sheepish for the most part but was assertive when he wanted to be, he was the teams captain anyway. So for the most part it was a toss up when it came to what people assumed he was. Most seemed to think he was a beta and a few had even mistaken him for an alpha due to the lingering scent of Tsukishima on him. Though Yamaguchi personally thought if he were to present he'd be a beta based on the family history he knew of so he quietly self identified as such. 

When Yamaguchi would inquire Tsukishima about what he thought the boys status would end up being when or if he ever presented the alpha brushed it off unwilling to give a friendly guess.

It started as a normal day on court, practice had just started and the gym filled with the sound of squeaky shoes, volleyballs and annoying yells.  
Yamaguchi was still getting used to encouraging the first years, he was still a little awkward when it came to instructions but had been making progress with them nonetheless. Tsukishima stood off the sidelines drinking water and watching Yamaguchi clumsily practice his serves with the newbies, seemingly stumbling even more than normal today. The alpha wasn’t quite in the mood to practice, it was an odd day for him, he felt inexplicably on edge. He stood zoning out on the sidelines for a while until he felt the glare of Ukai on his back, he sighed and casually made his way onto the court. Hinata chirped for him to join up with him and Kageyama to practice, the little omega practically dragged him over to join them.  
The alpha glanced back to Yamaguchi once more, his awkward movements now seemed more sluggish. The sight of this gave Tsuki an unsettled feeling that grew worse once he saw Yamaguchi suddenly fall to the floor.  
What happened?  
Had he hurt himself? 

A pained cry suddenly rang out from the boy, he grabbed his stomach and kicked his feet obviously in a great state of distress.  
Coaches ran over and shooed away the concerned first years to make room and assess what was going on.  
The room filled with confused panic, everyone stood unable to grasp the situation, Yachi had managed to take action by running to the nurse's office to alert them of what was happening but the rest of the room was still unable to do anything unsure if they should even try lifting the boy in such a state.  
He was breathing fast, his skin was completely flushed and was sweating profusely while practically screaming in pain. The sudden and drastic deterioration of his health was scary to say the least.

Students were instructed to exit the gym for health purposes, out of fear of it being some sort of disease, but no one seemed to exit, they all just stood as captivated observers both curious and concerned for their friends health.

Yamaguchi continued to whine and cry out in pain now viciously scratching at his scent glands. The action set off a giant red flag and as Takeda and Ukai turned to once again instruct students to leave it happened.  
A dead silence embraced the room, a needle could drop and it would sound louder than thunder. The sweet ripe smell of an omega in heat had gone off in the room like a nuclear explosion. Bodies became rigid, eyes locked onto the now omega Yamaguchi as he laid there no longer screaming; still in pain now breathing low husky breaths and writhing in a state of arousal.

Tsukishima stood in shock much like the rest of the team, unable to process what he was seeing and now what he was feeling. His eyes stayed deadlocked onto every detail of Yamaguchi's face as expressions of lust mixed with winces of anguish now continuously washed across his face. Catching Yamaguchi's teary yet hungry eyes meet his before closing and turning away in shame. 

The world seemed tense and frozen trapped in a stagnant hell of overwhelming shock and warmth for an uncomfortable amount of time. 

It wasn't until Tsukishima had noticed the movement of a second year alpha quickly move forward that he also felt himself move. His feet seemed to instinctively travel without thought towards Yamaguchi, rushing towards the newly presented omega Tsukishima's gaze quickly met with Hinata, the boys brown eyes pierced straight through him, they were the last thing he saw before the world suddenly went black.

Tsukishima opened his eyes to see two blurry faces looking down at him; there was an orange and black mass above him. He blinked and squinted but the image never became clear.  
"..My glasses." The alphas voice came out groggy and unsure.  
"Oh, yeah!" A familiar voice quickly responded placing his glasses into a free hand.  
Upon regaining clarity in more ways than one, the alpha realized he was on the ground and that it was Hinata and Kageyama who had been the ones overlooking him. He sat up and quickly turned his head to inspect the room.  
"What happened to me? Where's Yamaguchi?"  
The pair looked at each other oddly before getting the words out.  
"Yamaguchi presented as an omega, we got him out of here safely but you looked like you were gonna charge him so Kageyama, uh." Hinata fidgeted and blushed.  
"I knocked you out." Kageyama had a wide eyed matter of fact look on his face.  
It was then that Tsukishima felt the throbbing pain at the back of his head. Both Hinata and Kageyama were idiots in his mind but at least honest goodhearted ones even if it was annoying.  
"What.. that wasn’t what I was.. I thought I saw.." Tsukishima trailed off as the label of omega finally sank into his mind.  
"What?" Hinata questioned, cocking his head a bit to the side interested in where the alphas mind had gone.  
"Nothing.." Tsukishima remarked as he picked himself up from the gym floor to walk away. He didn't want to share with either of them what was on his mind but another uneasy concern grew in his gut.

Though practice had only just started it was obviously cancelled after the incident, leaving the gym to air out overnight. Everyone went home quietly still shaken up over the event. Tsukishima walked home with his headphones on but his mind wouldn't allow him to focus on the music it was filled with thoughts. 

When it comes to scents the only people who wouldn’t be affected by an omega in heat or alpha in rut would be a family member. Only genetic family members would be unaffected or essentially nose blind to another omega or alphas scent. Meaning a household of alphas could go about their day unbothered by an omega in heat in their household if they were related in some way; ie a parent, sibling, cousin and so one.  
But this then complicates things greatly for adopting children. Most all omegas and alphas are turned away from being able to adopt children simply for safety reasons. Regardless if the child presented as beta or not the scents would be overwhelming to grow up in. This essentially meant that only betas were allowed to adopt and foster children.

Yamaguchi was in fact adopted. He had been raised by a sweet beta couple, but this was something he never seemed to mention to anyone, not even to Hinata or Kageyama. It wasn’t that he was ashamed of his parents but it was something he had been bullied quite roughly for when he was younger. While Tsukishima knew and didn't at all seem to care about that fact Yamaguchi still treated it as a sore subject. 

Tsukishima wouldn’t out any of Yamaguchi's family situation but a curious anxiety wouldn't escape his mind. How were they going to handle it? Betas though not as affected by scent still couldn't handle the smell of an omega in heat. Would they have to avoid their child like the plague? The thought of Yamaguchi going through his first heat without a supportive family member in a cold empty house gave the boy a sour feeling.  
Though Tsukishima was young when Akiteru had gotten his first heat he distinctly remembered how much his mother had doted on him, making sure he stayed hydrated, well fed and comfortable. Whenever Akiteru had cried she ran to comfort and make sure all was well.  
Tsukishima didn't think Yamaguchi's parents would let anything bad happen to him but there was a concern as to how the boy would fare on his own, thinking about it made the alpha uneasy. Yamaguchi was in such an awkward position, presenting as late as he was, with a lack of guidance or knowledge of his situation it would obviously be stressful..


	2. Inspection

A concerning two weeks had gone by...  
No one on the team wanted to bring the topic up but the question of what happened to Yamaguchi was weighing heavy on everyone's mind. Tsukishima tried hard not to notice but he always felt a piece of his day was missing. When he walked to school, ate lunch and played volleyball it was noticeably lonely, it was like his shadow had left him. It was tolerable the first week but upon the second he knew something wasn’t right.  
He caught Hinata giving him a few worried looks when Yamaguchi hadn’t returned the following week, the little omega had also sensed something was wrong.  
Omegas heats usually lasted a week at most, so two was more than concerning.  
Tsuki had messaged his friend a few times after the first week feeling it wouldn't be any harm at that point but still a response never came, also concerning. 

Tsukishima wanted to stay level headed about the situation; he thought about what the most rational explanation for his absence might be and what came to mind was upsetting to him. Was Yamaguchi too embarrassed about his new status to come to school? The believability of the thought irritated the alpha, sure it'd be embarrassing to come back after putting on such a display in front of the whole team but it's not like he could’ve stopped himself from presenting. It'd be better to come back with dignity than make everyone worry even more, being a cowardly captain wasn't a good look.

Tsukishima felt a little anger seep into him, he was worried about Yamaguchi, more than most people would think he’d be. But he knew enough about heats to know this was too long, if his concerns were being wasted over the now omega having a big pity party then he’d have a few choice words to say to him.  
The alpha didn't think he had the ability to comfort the omega into feeling better about his gained status but he sure as hell wouldn’t let him wallow in it. 

At the end of practice that day Tsukishima made up his mind and quietly set off to Yamaguchi's house. 

Yamaguchi's residence was a cozy two story home, Tsukishima had been there many times when they were kids but over time he got less and less interested in visiting houses but the alpha did remember something that might be important from those days. 

The front door was of course locked and knocking led to no answer. He peeked through a few windows and didn’t see any signs of life, the house indeed looked empty, all the lights were off aside from a single light coming up from Yamaguchi's room. Seeing that only further peaked the alphas curiosity, so much so that he felt it warranted a “break in” to scope out the omegas situation.  
Tsukishima's big break in was done by simply checking to see if the family still kept a spare key under a false rock in the garden, Yamaguchi had pointed it out years ago, he even surprised himself by remembering it. The alpha felt smart and cheeky sneaking in but also a little guilty though he mentally justified his intrusion as a wellness check. 

Upon entering the home he was greeted with some darkness with the lights being off but aside from that it looked completely normal. Checking the kitchen he found Yamaguchi’s phone that had been left turned off on the counter. Seeing it there felt like a bad sign, shouldn’t he have his phone back by now? 

Seeing it there made him more uneasy but the only way the alpha felt he was going to get any sort of answer to what was going on was by checking Yamaguchi’s room…

He slowly walked up stairs to the boys room but as he got to the second level of the house the faint spells of omega suddenly hit his nose again. Conflicting feelings immediately arose inside him. Should he really be the one doing this? Maybe he should have gotten Hinata...  
He hesitated but ultimately dismissed the thoughts, his heat should be over by now and he should be the one to confront Yamaguchi when he needed to be set straight.

He reached the bedroom door and slowly opened it with a cautious hand.

The room was dim and hot, miserably hot, the scent of omega seemed to thicken the air in the room. It smothered the alpha immediately upon opening the door.  
It was a desirable scent but it was incredibly overstimulating, almost knocking the alpha off his feet. He leaned against the door frame for balance and peeked into the room. 

The source of the light was from a lamp next to Yamaguchi's bed, it spotlighted a half full water bottle. Tsuki noticed an alarming amount of empty bottles scattered the bottom of the bed along with blankets, dirty plates and soiled clothes. It was the dirtiest he had ever seen his friends room as he was usually very tidy.  
A soft cry interrupted Tsukis inspecting. The alphas head shifted to the bed itself, it looked like nothing but a mass of blankets at first but the mass started shifting to reveal Yamaguchi's face poking out. The poor boys cheeks were hollow, his skin pale as snow and eyes black and sunken. He blinked and softly whined seemingly waking up from a nap.  
It was a shock to see him in such a state, he looked like a corpse, it wasn’t exactly what Tsukishima had prepared himself for.  
“..Tsuki….” the omega murmured in a confused state still trying to open his eyes.  
Tsukishima felt frozen when hearing his name, he was confused and surprisingly turned on. Yamaguchi looked like hell but still seemed to emanate a powerful alluring scent that mixed with the omega calling his name sent Tsukishima up the wall. He wanted to explain himself but his mouth felt completely parched as though the heat of the room was getting to him. All he could do was lock eyes with the omega. 

“..Wait..” Yamaguchi quietly forced out the words and recoiled slightly back into his blankets.  
The soft command halted Kei, he had felt his foot move forward beneath him, he stopped and then realized he had moved from the doorway to the middle of the room without even realizing it..  
The alphas face flushed and he quickly backpedaled out of the room in his moment of clarity. Upon shutting the door his knees finally gave out and he sat against the wall in bewilderment. 

Fuck, Fuck, Fuck, Fuck

Fuck

Yamaguchi wasn’t out of his heat??? 

Tsuki couldn’t handle the panicked adrenaline he suddenly felt in the moment so he reactively bit into the flesh of his hand to somehow ground himself, the more his hand wanted to reach towards the door the harder he bit down. 

As he calmed himself a level of disgust washed over him. Yamaguchi looked so beaten down and sickly yet the instinctual urge to sexually dominate the omega was still present and forceful. The idea of assaulting an omega at any point was horrible but to imagine possibly doing so at such an absolutely weak and defenseless state made him queasy.  
Gross, he thought. 

While his assumption about Yamaguchi’s heat was for some reason completely wrong, he was right to worry about the omega’s ability to care for himself. He looked as though he wasn’t eating or sleeping enough at all, his hygiene both for his space as well as his body was in desperate need of help, he was wasting away on his own..

He wanted to help Yamaguchi, he needed to...

Hinata was the only omega he felt he could call to help; Sugawara was away at university and the alpha didn’t think Yamaguchi would be very comfortable if his mom or brother came to help. He reached for his phone, going through his contacts he managed to find Hinata, he got the tiny omegas number a long time ago when he had pestered him for help on some classes. He was annoyed by the shrimps messages at the time but he was now overwhelmingly grateful he had the boys number.

“Hey, Tsukishima, whats up?” An attentive Shoyo had quickly answered the call just after the first ring.

“It’s about Yamaguchi… I stopped by to see if he was okay and it’s ..not good. I was hoping you could come by to help him.” Tsukishima didn’t want to get into the details of things, he knew Hinata would be quick to aid regardless of what he added. 

“I’ll be right there!” The response was an excitable yell familiar to sounds the ginger would make on court, it was obnoxious but made the alpha a bit relieved. It was weird relying on Shoyo like this but the omega sure wouldn’t disappoint.


	3. Chapter 3

Tsukishima ended up waiting on the steps of Yamaguchi's house, he sat there trying his best to clear his mind of what was upstairs. He put his energy into taking controlled breaths, fresh air no scents, no unsettling thoughts, no nothing. 

Tsukishima wasn’t keeping track of time but he felt the orange haired omega popped into view much quicker than he imagined he would. Hintata stood panting for air before him, having obviously ran as fast as he could over, why the omega thought running over would be quicker than driving was beyond him.

“So-so what’s the deal?” Hinata practically coughed the words out in between breaths

“He’s still in heat I think, but he looks like death.. It's really bad.” Tsuki rubbed his knees uncomfortably trying his best not to think about it too much.

“Wow, what?!” 

“He might have to go to the doctor or something…”

“That sounds awful... I guess I can try to help..Are his parents not here looking after him or something??”

“Yamaguchi would be the person to tell you that..I don’t know where they are and it's a complicated situation anyway.”

“Oh, okay...And what about your hand? Why’s it all bloody?” Hinata's voice grew evermore concerning.

Tsukishima instinctively moved his exposed hand from Hinata's view, it wasn’t any of his business.   
“It’s nothing.” He stated evasively. “Just call me if anything bad happens alright.” He tossed the spare key to Hinata and swiftly got up from the step. Spending any more time near the house would feel like a mistake. 

“Alright then” Hinata remarked with a disgruntled look


	4. Details

Tsukishima watched Hinata intently the following day. Yamaguchi still hadn’t returned to school and Hinata had ghosted his texts asking for an update on the situation, in fact Hinata seemed like he was actively avoiding interactions with him.   
Tsukishima's desire for answers was driving him crazy and his annoyance grew every time Hinata turned away from his direction.  
Was the omega mad at him?  
Or worse, did something happen to Yamaguchi that he didn’t want to or couldn’t bring himself to tell the alpha?  
Thinking about it too much would destroy him.  
It wasn’t until he was leaving the gyms changing room that the omega caught him off guard with a sudden approach.

“We can talk after practice.” Hinata’s voice was unusually serious and to the point. His tone made Tsukishima uneasy but the promise of answers was enough to get through the rest of the day.

After practice he found Hinata outside the gym casually resting in the courtyard. He made his way over and joined him sitting on the grass.

“So what happ-”

“Why didn’t you tell me Yamaguchi was adopted?” Hinata had quickly and aggressively cut the alpha off and looked at him furiously for an explanation.  
Tsukishima sat quietly for a minute searching for the right words to say. 

“He used to get bullied for it so it’s something he liked to keep to himself. If you were going to find out I felt it was best he told you himself.”  
Hinata didn’t say anything but he continued to give Tsukishima a sour look.  
“Go ahead and be mad about it if you want, I don’t care. Just tell me if Yamaguchi is alright. What happened to him?” Tsukishima's response was cold, he didn’t feel like apologizing but there was no point in being petty over it. 

Hinatas face subtly turned from an angry to uncormfotable expression.   
“His parents talked to doctors who instructed they give him suppressants for his heat, since he’s presented so late it's likely he'll tend to have much greater intensity heats than an average omega would have.. But it looked obvious to me that he had an allergic reaction to the suppressants and they only made him feel more sick.”  
Hinata began pulling up grass out of frustration over the matter.  
“Doctors also advised his parents to stay at a separate location for the full duration of his heat and wait for Yamaguchi to call them when it's over. So no one was there to check up on him or see that he was having a bad reaction. No one was there to see if he was eating or even able to get up to open the window or get to the phone. All he ended up being able to do was lay there in a hot room being overwhelmed with his own scent forcing his body to stay in an elongated unbearable heat. ”  
The omega fell backwards onto the grass and let out a big huff.  
“It was genuinely awful.”

Tsukishima felt the hair on the back of his neck rise up hearing the information, it made him feel incredibly sick.  
“Where is he right now then?” Tsukishima asked concerning.

“He’s still home, now with his parents. I called them after I helped him shower and cleaned things up. He still needed another day to regain his strength so that's why he didn’t come today. He’ll be back tomorrow but thankfully he’s out of his heat right now.”

“Can you stay with him next time so this doesn’t happen?”

“What do you mean “next time”?” Hinata's gaze turned to the alpha puzzled.

“His next heat, he’ll have to go through it alone again.” 

“I already talked with him about how to care for himself during heats and even said I’d gift him a box of, um… toys, to make things more bearable.. I think he should hopefully be fine.” Both boys were a bit red faced upon hearing/saying the information. 

“Why can’t you stay with him through the duration of his next one just to be sure.” Tsukishima felt a deep anxiety grow in him. Having seen Yamaguchi in such a state left a mark in him, he never wanted Yamaguchi to feel that suffering again. 

“I know you’re scared for him but I don’t think you know how selfish that request is. I'm not his family member so it would affect me, I’d be sent into a heat as well, defeating the purpose of me being a carer. And I’m definitely not his mate..” Hinata looked squeamish about going into detail about what that would be like.

“Oh, sorry I asked.. Then are there other ways to lessen the stress of his heats besides suppressants?” The alpha coyly inquired.

“He’s really unlucky being allergic to them.. The only other thing I can think of is bonding, makes things go by quicker and way less painful.”

It was then that Kageyama had appeared in view from afar building across the way causing Hinata to spring up.  
“I’m gonna need to go, please don’t worry too much over Yamaguchi anymore.I took care of things, you should rest easy now. You’ll get to see him tomorrow!”  
Hinata jumped up and made his way across the courtyard practically running into Kageyama’s arms. The pair had bonded over summer and became, at least from Tsukishima's perspective, obnoxiously lovey on each other. Surprisingly Kageyama was the more affectionate one of the two, he'd constantly nuzzle and play with Hinata's hair, come up and hug the smaller boy from behind. It weirded Tsukishima out seeing them become so close since being first years but it didn't make practice a bit quieter.  
Seeing the two embrace this time didn’t make him as annoyed as it usually did, he instead felt oddly envious.


End file.
